Sterilisation of women may be made for many reasons. Generally it can also be said that there is a great need for sterilisation. There are also a number of different methods used. The most common method is to clamp or cut off the fallopian tubes by external surgery in order to hinder sperms from reaching the ovum. This is an external invasive method which as such is risky for the patient and requires hospital time. Several less invasive methods have been suggested to reduce the risks associated with surgical methods, and to reduce the costs for time and hospital care. Some less invasive methods are performed intracervically under direct visual observation by the use of a hysteroscope and a special catheter through which an agent can be introduced into the fallopian tube via the cornu of the uterus with the aim to block the fallopian tube. One such method is based on the use of a silicone plug sold under the name of OVABLOC. However, the method is difficult to perform, and there is also a risk that the silicone plug will fall out of the fallopian tube due to the powerful movements or spasms of the tube.
Other less invasive sterilisation methods include the administration of a toxic substance using a catheter introduced into the inlet of the fallopian tube. The toxic substance causes the tissue of the fallopian tube to necrotise and thus produces scar tissue which blocks the tube. However, such substances are not only toxic to the tissue of the fallopian tube, but also to the surrounding tissues. Since such toxic substances may enter into the abdominal cavity via the fallopian tube, there is a risk of serious damage. The manner in which to handle this problem is usually to thoroughly measure and monitor the volume of toxic substance introduced. Moreover, use of toxic substances as such should be limited to a minimum because of general safety and environmental concern. For the above reasons, this technique has not been used in the western world.
Furthermore, a method has also been proposed which involves the administration of hot sterile water by continuous infusion of the hot water through the fallopian tube, which can cause a part of the tissue of the fallopian tube to necrotise and thus produce scar tissue which, over some time, would block a part of the tube. The cooled water would then go down into the abdomen cavity. It is however vital that a temperature of at least 60-90° C., or even higher, is maintained in the part of the fallopian tube to be treated for a sufficient amount of time.
Medically, the fallopian tube comprises different sections as seen in its lengthwise direction and two sections suitable for treatment are the intramural section and the isthmus in particular. The intramural section, which is located close to the cornu, has the smallest diameter of about 1 mm and is approx. 10 mm long, and is highly vascularised. In the water infusion method described above, it is vital that a correct amount of hot sterile water is infused through the fallopian tube at a proper balance between infusion speed and water temperature. The blood circulation in the intramural section has a strong cooling effect and if the speed of the water is too low, the water may when reaching the isthmus section, already have been so cooled that no efficient sterilisation can occur. On the other hand, if the speed of the hot water is too high, hot water may pass through the fallopian tube to reach the abdominal cavity, with high risk for damage in the form of adhesions. Furthermore, large amounts of water in the abdominal cavity might be taken up by the vascular system, and subsequently cause major damage to the brain. The method seems not to have been used in practice.
There are also other methods suggested for the occlusion of the fallopian tubes by using catheters creating locally high temperature, based on radio frequency or electrically heated filaments. Such methods however require the use of a hysteroscope, which is a disadvantage. Furthermore, the catheters have to be introduced into the tubes to a sufficient length in order to assure 100% occlusion of the fallopian tube, with high risk for damage. In addition, such methods must be performed twice, i.e. once for each fallopian tube, thus increasing the risk for damage.
In this respect it is also vital to mention that the fallopian tube may obstruct such sterilisation methods. A tube may be fully or partially blocked, and although it may be fully blocked this needs to be confirmed. In some cases, a fallopian tube merely provides some resistance to the sterilisation instruments and/or substances and thus must to be opened, which is difficult to achieve. This step of confirmation of an open fallopian tube has to be performed initially as a separate step before the sterilisation method is performed.
It is therefore the object of the present invention to provide a sterilisation device, and sterilisation method using said device, that is non-invasive and which is simple to use, yet overcomes at least some of the disadvantages mentioned above. It should preferably also operable by someone other than a highly qualified gynaecologist and under conditions that would not necessitate a fully sterilised operating theatre.